1. Field of the Invention
Plasma arc torches can be used for either cutting or gouging depending on the configuration of the torch. This invention relates to a plasma arc torch used in the gouging mode. More specifically this invention relates to an improved front end assembly specifically for gouging. The front end assembly on most torches can be easily removed and a different front end assembly can be installed so that the same torch can be used for either cutting or gouging. This invention focuses on an improved front end assembly for gouging including a secondary gas nozzle and tip.
2. Description of Prior Art
In a typical metal welding shop three primary tools are used for manufacturing metal products, i.e. cutting apparatus, welding apparatus, and gouging apparatus. Welding is, of course, the primary means of joining different pieces of metal. From time to time a weld will be improper or it will not meet specification. Welds which do not meet specification can sometimes be detected visually but are also detected by x-ray and other means. When it is necessary to remove a weld, a device known as a gouger is frequently employed for this purpose. Air carbon arc torches, such as those manufactured by the Arcair Company of Lancaster, Ohio are frequently employed for gouging. In addition to weld removal, these devices are also used for back gouging, edge preparation, defect repair, and many other metal removal jobs. A gouger is sometimes referred to in the industry as the welder's eraser.
Plasma arc torches are old in the art and have long been used for metal cutting. More recently, plasma arc torches have also been used in a gouging mode as an alternative to conventional air carbon arc gouging.
For example, Thermal Dynamics Corporation of West Lebanon, N.H. has offered a plasma arc torch, as described in the information disclosure statement, for both cutting and gouging. The same torch can be assembled with one type of front end assembly for cutting; it can be reassembled with a different front end assembly and used for gouging. L-TEC Welding & Cutting Systems of Florence, S.C. also offers a plasma arc torch for gouging as discussed more fully in the information disclosure statement. The L-TEC version of a plasma arc gouging torch is also thought to be convertible to a cutting mode.
The larger models of air carbon arc gougers can typically remove more metal at a faster pace than conventional plasma arc gougers. However, the air carbon arc devices are loud and produce a large amount of slag and debris. The slag and debris can be difficult to clean up unless the surrounding surface area has been pre-treated with one of many release agents, well known in the industry. Also the air carbon-arc gouging process does not perform well on aluminum. In some situations, the plasma arc gouger is preferred to the air carbon arc gouger for various reasons.
Plasma gougers are generally not as noisy as air carbon arc gougers. The slag and debris created by plasma arc gougers is generally not as difficult to remove as the slag and debris created by an air carbon arc gouger. Because the plasma gougers do not use a carbon electrode, there is no expense associated with this type of consumable component. The operation of a plasma gouger is not disrupted by the need to repeatedly change a carbon electrode. The plasma gouger does not add undesirable carbon to the material being gouged. The plasma arc gouging process can gouge aluminum effectively. However, one drawback to conventional plasma gougers is the size and quality of the gouge path compared to the gouge path created by comparable air carbon arc gougers.
The present invention focuses on an improved front-end assembly for a plasma arc torch to enhance the size and quality of the gouge path.